Contrails
They can be interesting!
I have been sky gawking for many years and find trails can be of great interest.
Time was in the 60s/70s I could tell what A/C was trailing by the nature of the Trail. Lots of different types then Civil and Military. V bombers were very distinctive
I live in East Anglia and most recent enjoyment was A C130 Trailing in a Moonlit sky, like a Silver Ribbon combined with the unique sound.
I also like the trails at Sunset, makes for some nice photography.
Beauty is in the eye of the beholder.